File U_CVE-2025-49176-os-Check-for-integer-overflow-on-BigRequest-length.patch of Package xorg-x11-server

From 4fc4d76b2c7aaed61ed2653f997783a3714c4fe1 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Wed, 18 Jun 2025 08:39:02 +0200
Subject: [PATCH] os: Check for integer overflow on BigRequest length

Check for another possible integer overflow once we get a complete xReq
with BigRequest.

Related to CVE-2025-49176

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Suggested-by: Peter Harris <pharris2@rocketsoftware.com>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2028>
---
 os/io.c | 2 ++
 1 file changed, 2 insertions(+)

Index: xorg-server-21.1.15/os/io.c
===================================================================
--- xorg-server-21.1.15.orig/os/io.c
+++ xorg-server-21.1.15/os/io.c
@@ -395,6 +395,8 @@ ReadRequestFromClient(ClientPtr client)
                     needed = get_big_req_len(request, client);
             }
             client->req_len = needed;
+            if (needed > MAXINT >> 2)
+                return -(BadLength);
             needed <<= 2;
         }
         if (gotnow < needed) {